Memory leak in BAG dataset

[rprinceley]

There appears to be one or more cases of missing H5?close calls in the BAG implementation. This is causing memory leaks.

Also, we had to change nAttrSize in HDF5AttrIterate() from:

nAttrSize = H5Tget_size( hAttrTypeID );

to:

nAttrSize = H5Aget_storage_size( hAttrID );

Attached is a patch that adds these calls. We are still testing these, please review and include if appropriate.

[warmerdam]

I have reviewed and tested the patch and it seems good. Applied in trunk (r21650) and 1.8 branch (r21651).

Thanks!